Saturday, 13 January 2007
Using CALIPSO to study the influence of the Saharan Air Layer (SAL) on the intensity of tropical cyclones
The Saharan Air Layer (SAL) is a layer of warm, dry, dusty air which normally overlays the cooler more humid surface air of the Atlantic Ocean. Over the Sahara Desert from late spring to early fall, air moving across the desert becomes warm and dry forming a deep mixed layer in the troposphere. This layer can extend from 1,500-1,600m in the atmosphere, be traced as far west as the Gulf of Mexico, and is characterized by mineral dust, dry air, and strong winds. The Saharan Air Layer has been shown to help increase vertical wind shear and allow for the entrainment of dry air into a tropical wave, which aids in weakening tropical disturbances. The proposed research is to use CALIPSO data, which will play a vital role in obtaining better information on the altitude and thickness of clouds and aerosol layers to explore how the structures of tropical cyclones are affected when they interact with the SAL. With a successful CALIPSO mission, understanding the SAL's dynamic effects on tropical cyclones can be improved by providing vertically resolved images to be studied in order to improve weather predictions and climate models.